class A {
  String a2;
  void a() {
    print("a");
  }
}

class B {
  String b2;
  void b() {
    print("b");
  }
}

class C {
  void c() {
    print("c");
  }
}

class D {
  void c() {
    print("d");
  }
}

class AA extends A with B, D, C {}

class AB = B with A;
